1. Field of the Invention:
The present invention relates to a water dropping type irrigation pipe which is effective for irrigation and manuring (fertilizer application) in an agricultural and horticultural facility and which is compact, easily handling and economical.
2. Description of the Prior Art:
A water dropping irrigation is a system for supplying directly around roots of plants at low flow rate for a long time by reducing pressure of pressurized water through irrigation equipment laid on or under the soil surface. This is a novel irrigation system suitable for dried land and sandy land which has advantages of (1) water-saving; (2) yield increase; (3) salt injury inhibition; and (4) growth term shortening in comparison with the conventional furrow irrigation and a water spraying method.
The following water dropping type irrigation equipments have been known; (1) an irrigation nozzle having inner small diameter screw passage; and (2) a double wall pipe having many fine holes on inner and outer walls.
In these conventional irrigation equipments, it has been considered to reduce a flow rate and to prevent a serious reduction of flow rate at an end so as to irrigate uniformly even though a long pipe is used. However, the shape is complicated in being small whereby a complicated manufacturing manner is needed to cause low productivity and high cost, disadvantageously.
In manufacture of the irrigation nozzle, a precise injection molding is required. In manufacture of the double wall pipe, a combination of a profile extrusion molding or a heat melt bonding of ends of film and perforation are needed. In both cases, productivity could not be high enough and many products could not be prepared in parallel in one line in technical aspects. It has been difficult to reduce processing cost and to increase productivity in mass production by using a large molding machine. Beside such productivity, it has not been easy to lay down and take off equipment on a culture land. The equipment could not be wound compactly and it could not be easily moved or stored to cause trouble in a practical usage. Improved equipment has thus been required.